package cn.joey.rpc.registry;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.serialization.ClassResolvers;
import io.netty.handler.codec.serialization.ObjectDecoder;
import io.netty.handler.codec.serialization.ObjectEncoder;
import lombok.extern.slf4j.Slf4j;

/**
 * @auther liujiji
 * @date 2019/6/18 15:29
 */
@Slf4j
public class RpcRegistry {
    private int port;

    public RpcRegistry(int port) {
        this.port = port;
    }
    public void start(){
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer<SocketChannel>() {

                @Override
                protected void initChannel(SocketChannel ch) throws Exception {
                    ChannelPipeline pipeline = ch.pipeline();
                    //自定义协议解码器
                    /**
                     * 入参有5个，分别解释如下
                     * maxFrameLength: 框架的最大长度，如果帧的长度大于此值，则抛出TooLongFrameException
                     * lengthFieldOffset:长度字段的偏移量：即对应的长度字段在整个消息数据中的位置
                     * lengthFieldLength：长度字段的长度，如长度字段是int型表示，那么这个值就是4 long型是8
                     * lengthAdjustment：要添加到长度字段值的补偿值
                     * initialBytesToStrip：从解码帧中去除的第一个字节数
                     */
                    pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
                    //自定义协议解码器
                    pipeline.addLast(new LengthFieldPrepender(4));
                    //自定义参数类型编码器
                    pipeline.addLast("encoder", new ObjectEncoder());
                    //自定义参数类型解码器
                    pipeline.addLast("decoder", new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.cacheDisabled(null)));

                    //
                    pipeline.addLast(new RegistryHandler());

                }
            }).option(ChannelOption.SO_BACKLOG, 128).childOption(ChannelOption.SO_KEEPALIVE, true);

            ChannelFuture future = b.bind(port).sync();
            log.info("GP RPC Registry start listen at "+port);
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        new RpcRegistry(8080).start();
    }
}
